Internal combustion engines are supplied with a mixture of air and fuel for combustion within the engine that generates mechanical power. To maximize the power generated by this combustion process, the engine is often equipped with a turbocharged air induction system.
To prevent possible contamination and damage of internal engine components by debris ingested from the environment such as dust and other debris, engines typically use filters to separate dust and other debris from incoming engine air. For large displacement engines, and for engine applications on vehicles operating in harsh environments, pre-separators may also be used, upstream of an air filter, to remove larger debris particles from the air so as to prolong the service life of the filter and increase the maintenance interval of the machine in which the engine is installed.
Previously proposed pre-separators are typically of a centrifugal type. In such devices, incoming air is passed through spiral features or tubes within a generally cylindrical shaped housing such that particles suspended or carried into the housing with the incoming air are subjected to a centrifugal force and are thus forced to separate from the air. Particles thus separated are typically collected at the bottom of the housing and removed. Although centrifugal-type pre-separators are at least partially effective in removing larger debris particles from incoming air, they are not suitable for all types of operating environments. For example, machines operating in landfills, forests and other areas where large debris may be present such as leaves, twigs, paper shreds, cloth fibers and the like are present may be prone to having their pre-separators clogged with large debris. Pre-separator clogging, even when not severe, may increase the incoming air pressure drop of the engine, which can decrease the pumping efficiency and increase engine fuel consumption. Additionally, a severe clogging condition may render the engine inoperable and require service. Centrifugal-type pre-separators are especially prone to clogging from debris that is larger than the diameter of the air-swirling pipes used to generate the centrifugal force.